Hybrid vehicles potentially offer improvements in fuel efficiency and vehicle driving range over non-hybrid vehicles. Most hybrid vehicles are offered only in two wheel drive versions. Hybrid two wheel drive vehicles may often switch between providing motive power via solely by an engine, solely by a motor, or by a combination of the engine and the motor. However, the inventors herein have discovered that it may not be desirable to switch between power sources of a four wheel drive vehicle in the same way as is done for a two wheel drive vehicle. For example, in a four wheel drive mode, it may not be desirable to operate the motor according to a same schedule as when the vehicle is operated in a two wheel drive mode. Further, switching between driveline propulsion modes during varying road conditions may increase driveline degradation.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method for adjusting operation of a hybrid vehicle driveline, comprising: providing a manual driver input for a driveline operating mode parameter; and adjusting engaging of a driveline disconnect clutch positioned between an engine and a motor in response to the driveline operating mode parameter.
By adjusting operation of a driveline disconnect clutch in response to a driver input, it may be possible to limit engagements of a disconnect clutch during conditions where high driveline torque may be present so that the possibility of driveline degradation may be reduced. Further, by providing control of a driveline disconnect clutch to a driver, it may be possible to operate the vehicle driveline in a different manner than that which is useful for driving the vehicle on urban streets.
The present description may provide several advantages. Specifically, the approach may reduce business of shifting between driveline modes. Further, the approach may improve vehicle drivability. Further still, the approach may reduce driveline wear, thereby increasing the operating life of the driveline.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.